Reaction of a heterotopic P,SAs ligand with group 10 metal(ii) complexes: As–S bond cleavage and the formation of two unusual trinuclear structural isomers for Pd and Pt

Abstract

The synthesis of the heterotopic P,SAs ligand, 1-Ph₂AsSC₆H₄-2-PPh₂ (1) and its reaction with [PdCl₂(cod)], [PtI₂(cod)] (cod = 1,5-cyclooctadiene) and NiCl₂·6H₂O is reported. Cleavage of the As–S bond of 1 and coordination of the resulting phosphanylthiolato ligand (SC₆H₄-2-PPh₂)⁻ (SC₆H₄-2-PPh₂ = P,S) was observed with formation of [M(P,S)₂] (M = Ni, Pd, Pt). In the case of Pd and Pt, not only the mononuclear complexes [M(P,S)₂] formed, but also the trimers of [MX(P,S)] ([MX{(μ-S-SC₆H₄-2-PPh₂)-κ²S,P}]₃ [M = Pd, X = Cl (2) and M = Pt, X = I (4)]). Formation of 2 and 4 was preceded by the trinuclear isomeric intermediates [(cis-M{(μ-S-SC₆H₄-2-PPh₂)-κ²S,P}₂)-MX₂-MX{(μ-S-SC₆H₄-2-PPh₂)-κ²S,P}] [M = Pd, X = Cl (3) and M = Pt, X = I (5)]. The crystal structures of 1–5 and a possible reaction mechanism that leads to 2 and 4 are presented.